Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752623AbaG3WE0 (ORCPT ); Wed, 30 Jul 2014 18:04:26 -0400 Received: from unicorn.mansr.com ([81.2.72.234]:49697 "EHLO unicorn.mansr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752017AbaG3WEZ convert rfc822-to-8bit (ORCPT ); Wed, 30 Jul 2014 18:04:25 -0400 From: =?iso-8859-1?Q?M=E5ns_Rullg=E5rd?= To: Richard Henderson Cc: linux-kernel@vger.kernel.org, mcree@orcon.net.nz, linux-alpha@vger.kernel.org Subject: Re: [PATCH 1/2] alpha: Remove "strange" OSF/1 fork semantics References: <1406756552-23864-1-git-send-email-rth@twiddle.net> <1406756552-23864-2-git-send-email-rth@twiddle.net> Date: Wed, 30 Jul 2014 23:04:20 +0100 In-Reply-To: <1406756552-23864-2-git-send-email-rth@twiddle.net> (Richard Henderson's message of "Wed, 30 Jul 2014 11:42:31 -1000") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Richard Henderson writes: > The assignment to regs->r20 kills the original tls_val input > to the clone syscall, which means that clone can no longer be > restarted with the original inputs. > > We could, perhaps, retain this result for true fork, but OSF/1 > compatibility is no longer important. Note that glibc has never > used the r20 result value, instead always testing r0 vs 0 to > determine the child/parent status. What effect does this have on OSF/1 compat? > This failure can be seen in the glibc nptl/tst-eintr* tests. > > Reported-by: Michael Cree > Signed-off-by: Richard Henderson > --- > arch/alpha/kernel/process.c | 2 -- > 1 file changed, 2 deletions(-) > > diff --git a/arch/alpha/kernel/process.c b/arch/alpha/kernel/process.c > index 1941a07..77028d7 100644 > --- a/arch/alpha/kernel/process.c > +++ b/arch/alpha/kernel/process.c > @@ -278,8 +278,6 @@ copy_thread(unsigned long clone_flags, unsigned long usp, > *childregs = *regs; > childregs->r0 = 0; > childregs->r19 = 0; > - childregs->r20 = 1; /* OSF/1 has some strange fork() semantics. */ > - regs->r20 = 0; > stack = ((struct switch_stack *) regs) - 1; > *childstack = *stack; > childstack->r26 = (unsigned long) ret_from_fork; > -- > 1.9.3 > -- M?ns Rullg?rd mans@mansr.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/